This invention relates to the field of programmable tone generators for keyboard musical instruments, and more particularly to the capability of instant switching of the program of the tone generator from one musical scale to another.
Programmable musical instruments such as those in U.S. Pat. Nos. 3,821,460 and 3,939,751, assigned to the assignee of the present invention, have been reprogrammed by manually resetting the appropriate switches in a bank of 120 switches per keyboard. While reprogramming a keyboard could be accomplished in a minute or less by a person skilled in the programming technique, it became apparent that it would be highly desirable to have instant retuning capability. Ideally, retuning should be accomplished by preset programming of a number of scales which would then be instantly available to a performer and which could be reprogrammed as desired. Further information regarding programmable musical instruments may be found in the above-mentioned patents.